The present invention relates to an image inputting apparatus for inputting radiation image information used mainly in a medical field and to an image inputting method.
There is known an image inputting apparatus that projects radial rays on a subject from a radiation generating apparatus and reads a radiation image formed by radiations penetrated through a subject to input image information. The image inputting apparatus of this kind includes a system (CR type) wherein a stimulable phosphor plate storing therein radiation image information is scanned by a laser beam, then, accelerated phosphorescence light thus generated is converged and then is converted photoelectrically by a photomultiplier (hereinafter referred sometimes to as “PMT”) into electric signals, and a system (FPD type) that has a function to convert X-ray energy penetrated through a subject to be projected into electric signals to be structured again as an X-ray transmission image and is composed of a plate-shaped radiation image flat panel detector (X-ray flat panel detector) having a plane with an area that covers fully a portion of a human body necessary for image diagnostics.
For example, when conducting sensitivity compensation in an image inputting apparatus of a CR type, a calculation has been used for obtaining a sensitivity-offset value (value of setting voltage for PMT) for outputting ideal signal values from characteristic data concerning voltage and an amount of light of PMT and from signal values of PMT in the case of radiographing for sensitivity compensation.
In the convention CR type of this kind, when conducting sensitivity compensation, there have been needed voltage of PMT, characteristic data for an amount of light, ideal signal values and radiographing, resulting in inconvenience of obtaining and inputting of characteristic data, and further, a precision of sensitivity compensation has been low because of increased dominant causes for errors generated in numerical expressions and calculations.